1. Field of the Invention
The invention relates to a solid-state imaging device, a method for driving the solid-state imaging device and a camera.
2. Description of the Related Art
In a solid-state imaging device of related art, the same exposure time is applied to all pixels on the imaging plane. Even in the technology that enables a wide dynamic range by applying multiple numbers of exposure time in multiple imaging operations and integrating the resultant images (see JP-A-2004-363666, for example), the same exposure time is applied to all pixels. Thus, in a mixed pixel configuration in which some pixels have different sensitivity from the other, selection will be made in such a way that a short exposure time is set to prevent saturation of the pixels having high sensitivity, or a long exposure time is set to obtain a sufficiently large signal from the pixels having low sensitivity but saturate the high-sensitivity pixels. In this description, pixels having high sensitivity (high-sensitivity pixels) refer to pixels having higher sensitivity than pixels having low sensitivity (low-sensitivity pixels).
For example, when the exposure time is set such that the pixels having high sensitivity are not saturated, sufficient signal charge will not be obtained from the pixels having low sensitivity, resulting in a reduced S/N ratio. On the other hand, when the exposure time is set such that sufficient signal charge will be obtained from the pixels having low sensitivity, the pixels having high sensitivity are undesirably saturated.